The broad aim of this proposal is to develop an advanced tool for neuroscience research that is designed to facilitate critically important systems-level neuroscience research with long term goals of further advancing our understanding of brain function as well as ultimately improving therapies for patients suffering from neurophysiological disorders. The device described here will integrate advanced state-of-the-art technologies into a single, cost effective ensemble single-unit recording/inactivating (lesioning) device. Developing this integrated recording/lesioning tool will facilitate complex systems-level neurophysiology experimentation in small mammals that is efficient, well controlled, reliable, and repeatable. The device will consist of 3 major sub-assemblies: 1) a movable array of 16 ultra-fine wire, high impedance microelectrodes; 2) an ultra-compact microdrive capable of precise movement of the electrodes; 3) a miniature Thermo- Electric cooling unit, built around a commercially available Peltier device, that is capable of reversibly inducing functional inactivation of focal regions of cerebral cortex by local cooling. This device will allow simultaneous ensemble recordings and focal inactivations to be performed within multiple interconnected structures in a neural circuit. This will allow sophisticated systems-level neurophysiological experimentation to be performed that is not possible using other currently available techniques and/or methodologies. The device will be functionally tested in vivo, through a series of experiments, including acute implantation in primary somatosensory cortex of anesthetized rats, and chronic implantation in primary motor cortex of awake behaving rats. Successful development of a device such as this would provide an important new tool for neuroscience research that would have a very wide range of applications that extend from basic neuroscience research to clinical applications. An advanced, state-of-the-art recording/inactivating research device is described that is designed to facilitate our understanding of a number of important questions related to how our brain functions. Understanding these critical neuroscience related questions will facilitate development of improved therapies for a wide range of neurophysiological disorders. [unreadable] [unreadable]